Garrard English Mantle Clock runs too fast

by Kelly Mayer
(London, UK)

I have a Garrard (UK manufacturer) mantle clock, approximately 100 years old. It has three areas to wind it on its face. The clock is running too quickly. Do you have an idea of how I can slow the pace down so it keeps proper time? I'm guessing I can do something with the pendulum inside by adjusting the weight height somehow. Thank you!